In-vehicle radar device and cover for in-vehicle radar device

ABSTRACT

An in-vehicle radar device which radiates electromagnetic waves and receives reflected waves, from an object, of the electromagnetic waves so as to detect a location of the object and which is mounted on a rear of a vehicle, the in-vehicle radar device including: a transmission-and-reception section that transmits the electromagnetic waves and receives the reflected waves; a detection section that detects the location of the object based on the reflected waves; and a cover member that is provided below a rear bumper of the vehicle and that covers the transmission-and-reception section in a manner that a rear surface of the cover member faces a transmission-and-reception surface of the transmission-and-reception section so as to be spaced apart therefrom.

CROSS REFERENCE TO RELATED APPLICATION

The present application is a divisional of U.S. application Ser. No.12/670,558, filed on Jan. 25, 2010, which was the National Stage ofInternational Application No. PCT/JP09/00898, filed on Feb. 27, 2009.application Ser. No. 12/670,558 is hereby incorporated by reference inits entirety.

TECHNICAL FIELD

The present invention relates to an in-vehicle radar device and a coverfor the in-vehicle radar device, and more particularly to an in-vehicleradar device and a cover for the in-vehicle radar device which aremounted on the rear of a vehicle.

BACKGROUND ART

Conventionally, a radar device is developed which is mounted on avehicle and detects an object around the vehicle. When such a radardevice is mounted on the vehicle and exposed, there is a possibilitythat the radar device is weathered to cause malfunction. Further, whenthe radar device is mounted on the vehicle and exposed, the vehicle'sappearance is likely to be defaced. Accordingly, when the radar deviceas described above is mounted on the vehicle, a cover for covering theradar device is mounted on the vehicle together with the radar device.

Patent Document 1 discloses the radar device as described above. Theradar device disclosed in the Patent Document 1 has a radome portionthrough which electromagnetic waves transmitted from and received by aradar main body are transmitted. The radar main body is mounted inside avehicle's bumper, and the above-described radome portion is formed as apart of the vehicle's bumper.

-   Patent Document 1: Japanese Laid-Open Patent Publication No.    11-231041

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention

The radome portion disclosed in Patent Document 1 is mounted on thebumper of the vehicle, so that, when it rains, for example, there is apossibility that water drops, mud or the like sometimes adhere to thesurface of the radome portion.

FIG. 9 is a diagram illustrating a state where water drops coming frombelow adhere to the radome portion of the conventional radar devicemounted at the rear end portion of the vehicle. FIG. 9 is a sectionalside view illustrating a radar unit 61, a radome portion 62 which coversthe radar unit 61, and a bumper 63 to which the radome portion 62 isattached. The radar unit 61 is arranged inside the bumper 63 andtransmits and receives electromagnetic waves at itstransmission-and-reception surface 62S. In FIG. 9, a propagation regionof the electromagnetic waves is indicated by a region enclosed by dashedlines. Further, in FIG. 9, water drops are schematically represented ascircles, and directions from which the water drops are coming areschematically represented by arrows.

When the vehicle runs in the rain, for example, water drops are thrownup from below the bumper 63 due to a wheel rotation, an aerodynamicforce or the like, the water drops sometimes adhere to the surface ofthe radome portion 62 as illustrated in FIG. 9. Accordingly, when thewater drops adhere to the surface of the radome portion 62 in an areathrough which the electromagnetic waves transmitted from or received bythe radar unit 61 are transmitted, the electromagnetic waves are, forexample, sometimes absorbed by the water drop to result in attenuationof the electromagnetic waves. As described above, when theelectromagnetic waves are attenuated, the radar unit 61 sometimesbecomes unable to accurately measure a propagation distance or the likeof the electromagnetic waves. That is, the conventional radar device issometimes incapable of preventing the water drops from adhering to theradome portion, and consequently incapable of accurately detecting alocation of an object which reflects the electromagnetic waves.

The present invention has been proposed in view of the above-describedproblem, and an object of the present invention is to provide anin-vehicle radar device which is capable of accurately detecting anobject and a cover for the in-vehicle radar device.

Solution to the Problems

The present invention has the following features to achieve the objectmentioned above. That is, a first aspect of the present invention is anin-vehicle radar device which radiates electromagnetic waves andreceives reflected waves, from an object, of the electromagnetic wavesso as to detect a location of the object. The in-vehicle radar deviceincludes: a transmission-and-reception section that transmits theelectromagnetic waves and receives the reflected waves; a detectionsection that detects the location of the object based on the reflectedwaves; and a cover member that covers the transmission-and-receptionsection in a manner that a rear surface of the cover member faces atransmission-and-reception surface of the transmission-and-receptionsection wherein the cover member includes at least: a cover portion thatcovers the transmission-and-reception surface; and a lower protrusionportion that is provided below the cover portion and formed so as toprotrude on a surface side of the cover member with respect to the coverportion, the cover portion being formed of a material through which theelectromagnetic waves are transmitted.

In a second aspect based on the first aspect, the cover member furtherincludes an upper protrusion portion which is provided above the coverportion and formed to protrude on the surface side of the cover memberwith respect to the cover portion so as to prevent water drops comingfrom above and dirt-containing water drops coming from above fromadhering to a surface of the cover portion.

In a third aspect based on the second aspect, the cover portion, thelower protrusion portion, and the upper protrusion portion areintegrally formed.

In a fourth aspect based on the first aspect, the cover member isattached to a lower portion of a rear bumper of a vehicle.

In a fifth aspect based on the fourth aspect, the in-vehicle radardevice further includes: crash risk determination section thatdetermines whether or not a risk of a crash between the object and thevehicle is high based on the detected location of the object; andinformation section that provides information to rearward of the vehicleof the risk of a crash when the risk of a crash between the object andthe vehicle is determined to be high.

In a sixth aspect based on the fourth aspect, the in-vehicle radardevice further includes: crash risk determination section thatdetermines whether or not a risk of a crash between the object and thevehicle is high based on the detected location of the object; andoccupant protection section that protects an occupant in the vehiclefrom the risk of a crash when the risk of a crash between the object andthe vehicle is determined to be high.

In a seventh aspect based on the sixth aspect, the occupant protectionsection protects the occupant from a crash impact when the risk of acrash between the object and the vehicle is determined to be high, bymaking a headrest move forward so as to hold the head of the occupant.

In an eighth aspect based on the first aspect, the cover portion ismolded from a synthetic resin through which the electromagnetic wavesare transmitted.

A ninth aspect is a cover for an in-vehicle radar device, the covercovering a transmission-and-reception section, which is provided on thein-vehicle radar device, for the electromagnetic waves such that a rearsurface of the cover faces a transmission-and-reception surface of thetransmission-and-reception section, the in-vehicle radar deviceradiating the electromagnetic waves and receiving reflected waves, froman object, of the electromagnetic waves so as to detect a location ofthe object. The cover includes at least: a cover portion that covers thetransmission-and-reception surface; and a lower protrusion portion whichis provided below the cover portion and formed so as to protrude on asurface side of the cover member with respect to the cover portion inorder to prevent water drops from below and dirt-containing water dropsfrom below from adhering to the surface of the cover portion, the coverportion being formed of a material through which the electromagneticwaves are transmitted.

Effect of the Invention

According to the first aspect, the water drops or the like thrown upfrom below due to a wheel rotation of the vehicle, for example, areprevented from adhering to the surface of the cover portion.Accordingly, the electromagnetic waves are prevented from beingattenuated, and the location of an object is accurately detected.

According to the second aspect, the water drops such as rain drops orthe like from above are prevented from adhering to the surface of thecover portion whereby the location of the object is accurately detected.Accordingly, the electromagnetic waves are prevented from beingattenuated, and the location of the object is accurately detected.

According to the third aspect, as compared to a case where the coverportion, the lower protrusion portion, and the protrusion portion areseparately formed and assembled, the cover member is constructed atlower cost.

According to the fourth aspect, the cover member can serve as aso-called rear under spoiler. Accordingly, the location of the objectbehind the vehicle can be accurately detected, as well as an excellentdesign and aerodynamic characteristics can be provided at low cost.

According to the fifth aspect, the risk of a crash between the vehicleand the object is accurately determined based on information of theaccurately detected location of the object. Further, when anothervehicle approaches from behind the vehicle, on which the in-vehicleradar device is mounted, and the risk of a crash is increased, a driverof the other vehicle behind can be informed of the risk so as to alertthe driver to avoid the crash.

According to the sixth aspect, the risk of a crash between the vehicleand the object is accurately determined based on information of theaccurately detected location of the object. Further, when anothervehicle approaches from behind the vehicle, on which the in-vehicleradar device is mounted, and the risk of a crash is increased, anoccupant protection device, for example, mounted on the vehicle isallowed to operate. Accordingly, even when the other vehicle behindactually crashes, an occupant is protected from a crash impact.

According to the seventh aspect, when the other vehicle behind actuallycrashes, a head of an occupant is protected so as to be prevented from awhiplash injury or the like.

According to the eighth aspect, the synthetic resin material, which iseasily cast in a mold and inexpensive, can be used to construct thecover portion.

The radar cover described in the ninth aspect plays a part in theabove-described in-vehicle radar device, thereby providing similareffects.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagram illustrating a configuration of an in-vehicle radardevice according to a first embodiment, and a state where the in-vehicleradar device is mounted on a vehicle.

FIG. 2 is a vertical cross-sectional view of a radar cover, according tothe first embodiment, mounted on the vehicle.

FIG. 3 is a top view of the radar cover according to the firstembodiment.

FIG. 4 is a front view of the radar cover according to the firstembodiment.

FIG. 5 is a diagram illustrating a state where water drops coming frombelow adhere to the radar cover according to the first embodiment.

FIG. 6 is an exemplary flowchart illustrating processing executed by aprocessing unit 112.

FIG. 7 is a cross-sectional view of a radar cover, according to a secondembodiment, mounted on a vehicle.

FIG. 8 is a diagram illustrating a state where water drops coming frombelow and above adhere to the radar cover according to the secondembodiment.

FIG. 9 is a diagram illustrating a state where water drops coming frombelow adhere to a radome portion of a conventional radar device mountedon the rear of a vehicle.

DESCRIPTION OF THE REFERENCE CHARACTERS

11, 61 radar unit

12, 22 radar cover

13 hazard lamp

50 rear bumper

62 radome portion

63 bumper

100 vehicle

111 antenna

112 processing unit

BEST MODE FOR CARRYING OUT THE INVENTION First Embodiment

An in-vehicle radar device according to a first embodiment of thepresent invention is described below. Initially, a configuration of thein-vehicle radar device according to the first embodiment is describedwith reference to FIG. 1. FIG. 1 is a diagram illustrating theconfiguration of the in-vehicle radar device according to the firstembodiment, and a state where the in-vehicle radar device is mounted ona vehicle. In the following description, an example where the in-vehicleradar device is mounted on a vehicle 100 is described.

The in-vehicle radar device according to the first embodiment includes aradar unit 11 and a radar cover 12. The radar unit 11 is mounted on thevehicle 100 so as to be located inside a rear bumper 50 of the vehicle100. In the rear bumper 50, an opening portion is formed through whichelectromagnetic waves transmitted from the radar unit 11 aretransmitted. The radar cover 12 is attached to the rear bumper 50 so asto cover the opening portion of the above-described rear bumper 50.Here, any method may be used as a method for attaching the radar cover12 to the rear bumper 50. For example, the radar cover 12 may be fixedto the rear bumper 50 by bolts, or the radar cover 12 may be attached tothe rear bumper 50 by using an adhesive agent, an adhesive tape or thelike.

The radar unit 11 includes an antenna 111 and a processing unit 112.

The antenna 111 is an antenna device which transmits electromagneticwaves, and receives reflected waves, obtained by reflection of theelectromagnetic waves by an object. The antenna 111 is electricallyconnected with the processing unit 112, and outputs, to the processingunit 112, signals indicating phase information, intensity information,and the like of the received reflected waves. Atransmission-and-reception portion described in claims corresponds tothe antenna 111, for example.

The processing unit 112 is typically a control unit which includes, forexample, an information-processing unit such as a CPU (CentralProcessing Unit) or the like, a storage device such as a memory or thelike, and an interface circuitry. The processing unit 112 detects, basedon the phase information, the intensity information, and the like of thereflected waves inputted through the antenna 111, a location of theobject which has reflected the electromagnetic waves. Here, anyconventionally known method can be used as a method in which theprocessing unit 112 detects the location of the object. The processingunit 112 is electrically connected to a hazard lamp 13 mounted on thevehicle 100. The processing unit 112 calculates a risk of a crashbetween the detected object and the vehicle 100, and when the risk of acrash between the detected object and the vehicle 100 is high, outputs,to the hazard lamp 13, an indication signal for making the hazard lamp13 blink (see FIG. 6 described later).

The radar cover 12 is a member formed of a material through which theelectromagnetic waves transmitted from and received by the antenna 111are transmitted. For example, the radar cover 12 is molded by using asynthetic resin. A shape of the radar cover 12 is described below indetail with reference to FIG. 2, FIG. 3, and FIG. 4. A cover memberdescribed in claims corresponds to the radar cover 12, for example.

FIG. 2 is a vertical cross-sectional view of the radar cover 12,according to the first embodiment, mounted on the vehicle. Asillustrated in FIG. 2, the radar cover 12 has a cover portion 12α and alower protrusion portion 12β.

The cover portion 12α is a portion which covers atransmission-and-reception surface 111S at which the antenna 111transmits and receives the electromagnetic waves. In FIG. 2, apropagation region of the above-described electromagnetic waves isindicated by a region enclosed by dashed lines. As illustrated in FIG.2, the propagation region of the electromagnetic waves overlaps theradar cover 12 only in the cover portion 12α. That is, theelectromagnetic waves transmitted from and received by the antenna 111are propagated through the radar cover 12 at the cover portion 12α.

The lower protrusion portion 12β is a portion which is provided belowthe cover portion 12α and which protrudes on a surface side of the radarcover 12 with respect to the cover portion 12α.

FIG. 3 is a top view of the radar cover 12 according to the firstembodiment. FIG. 4 is a front view of the radar cover 12 according tothe first embodiment. As illustrated in FIG. 3 and FIG. 4, the radarcover 12 has a shape extending along the rear bumper 50 in a lateraldirection of the vehicle 100. The lower protrusion portion 12β similarlyhas a wing-like shape extending along the rear bumper 50 in the lateraldirection of the vehicle 100. Here, FIG. 2 is the cross-sectional viewof the radar cover 12 illustrated in FIG. 4 along A-A.

The cover portion 12α and the lower protrusion portion 12β can beintegrally formed by a molding method, for example, where a syntheticresin is injected into a mold. When the cover portion 12α and the lowerprotrusion portion 12β are integrally formed, the above-described radarcover 12 can be easily constructed at low cost. Alternatively, the coverportion 12α and the lower protrusion portion 12β may be separatelyformed and thereafter assembled so as to construct the above-describedradar cover 12.

Owing to the above-described shape and mounted position, the radar cover12 plays a role as a so-called rear under spoiler. That is, an excellentdesign and aerodynamic characteristics are provided by the radar cover12. Further, owing to the above-described shape, the radar cover 12 iscapable of preventing water drops and dirt coming from below fromadhering to the cover portion 12α.

A state where water drops and dirt are prevented from adhering to thecover portion 12α is described below with reference to FIG. 5. FIG. 5 isa diagram illustrating a state where water drops coming from belowadhere to the radar cover 12 according to the first embodiment.

In FIG. 5, water drops are schematically represented as circles, anddirections from which the water drops are coming are schematicallyrepresented by arrows. For example, when the vehicle 100 runs on a wetroad, water drops are sometimes thrown up from below due to a wheelrotation, an aerodynamic force or the like. In such a case, the waterdrops thrown up from below the radar cover 12 adhere to an under surfaceof the lower protrusion portion 12β which protrudes on the surface sidewith respect to the cover portion 12α, so that the water drops do notadhere to the cover portion 12α which is located above and behind thelower protrusion portion 12β. That is, the lower protrusion portion 12βplays a role as a so-called mudguard, thereby preventing the water dropsfrom adhering to the cover portion 12α.

As described above, the radar cover 12 according to the first embodimentof the present invention prevents the water drops from adhering to thecover portion 12α through which the electromagnetic waves transmittedfrom and received by the antenna 111 are transmitted, thereby preventingattenuation of the electromagnetic waves. Accordingly, the processingunit 112 accurately measures a propagation distance or the like of theelectromagnetic waves, thereby accurately detecting the location of theobject which has reflected the electromagnetic waves.

The processing unit 112 determines the risk of a crash between theobject and the vehicle 100 based on the detected location of the object.An example of processing executed by the processing unit 112 isdescribed below with reference to FIG. 6. FIG. 6 is an exemplaryflowchart illustrating the processing executed by the processing unit112. The processing unit 112 starts the processing in step A1 of theflowchart illustrated in FIG. 6 when, for example, an ignition switch ofthe vehicle 100 is set to on.

In step A1, the processing unit 112 determines whether or not the objectis detected. Specifically, the processing unit 112 determines whether ornot signals indicating phase information and intensity information ofreflected waves are received from the antenna 111. Hereinafter, theobject detected in step A1 is referred to as a detected object. Whendetermining that the object is detected, the processing unit 112proceeds the processing to step A2. On the other hand, when determiningthat the object is not detected, the processing unit 112 returns theprocessing to step A1.

Based on processing in step A1, the processing unit 112 waits forexecution of processing from step A2 to step A6 until the object isdetected.

In step A2, the processing unit 112 calculates a velocity V and adistance L. The velocity V is a relative velocity between the detectedobject and the vehicle 100. The distance L is a distance from thevehicle 100 to the detected object. The processing unit 112 calculatesthe distance L and the velocity V based on the phase information and theintensity information of the reflected waves. Here, any conventionallyknown method can be used as a calculation method of the distance L andthe velocity V. When processing in step A2 is completed, the processingunit 112 proceeds the processing to step A3.

In step A3, the processing unit 112 calculates a crash estimated timeTTC. The crash estimated time TTC is a time which is estimated to betaken until the detected object crashes into the vehicle 100. Theprocessing unit 112 calculates the crash estimated time TTC based on thefollowing equation (1).

TTC=L/V   (1)

When processing in step A3 is completed, the processing unit 112proceeds the processing to step A4.

In step A4, the processing unit 112 determines whether or not the crashestimated time TTC is equal to or less than a threshold value TH. Thethreshold value TH is a constant preliminarily stored in the storage ofthe processing unit 112, and is a reference value for determiningwhether or not the risk of a crash between the detected object and thevehicle 100 is high. When determining that the crash estimated time TTCis equal to or less than the threshold value TH, in other words, whendetermining that the risk of a crash between the detected object and thevehicle 100 is high, the processing unit 112 proceeds the processing tostep A5 so as to make the hazard lamp 13 blink. On the other hand, whendetermining that the crash estimated time TTC is greater than thethreshold value TH, in other words, when determining that the risk of acrash between the detected object and vehicle 100 is low, the processingunit 112 proceeds the processing to step A6 skipping processing in stepA5.

In step A5, the processing unit 112 makes the hazard lamp 13automatically blink. Specifically, the processing unit 112 outputs, tothe hazard lamp 13, an indication signal for making the hazard lamp 13blink. When receiving the above-described indication signal, the hazardlamp 13 blinks. When processing in step A5 is completed, the processingunit 112 proceeds the processing to step A6.

In step A6, the processing unit 112 determines whether or nottermination processing is executed. Specifically, the processing unit112 determines, for example, whether or not the ignition switch of thevehicle 100 is set to off. When determining that the terminationprocessing is executed, the processing unit 112 terminates theprocessing of the flowchart illustrated in FIG. 6. On the other hand,when determining that the termination processing is not executed, theprocessing unit 112 returns the processing to step A1 and repeatedlyexecutes the above-described processing.

Based on the processing from step A2 to step A5 executed by theprocessing unit 112, whether or not the risk of a crash between thevehicle 100 and the vehicle behind is high is determined, and when therisk of a crash between the vehicle 100 and the detected object is high,the hazard lamp 13 is made to blink so as to inform a driver in thevehicle behind of the risk of a crash, for example. Further, the radarcover 12 allows the location of the object to be accurately detected, sothat the processing unit 112 is capable of accurately detecting the riskof a crash between the vehicle 100 and the vehicle behind. Note thatrisk of a crash determination section described in claims corresponds,for example, to the processing from step A2 to step A4 executed by theprocessing unit 112. Further, information section described in claimscorresponds, for example, to the processing in step A5 executed by theprocessing unit 112 and the hazard lamp 13.

Second Embodiment

In the above-described first embodiment, an example where the radarcover 12 has the lower protrusion portion 12β, which is formed so as toprotrude on a surface side of the radar cover 12, below the coverportion 12α. However, the radar cover 12 may be constructed in a formfurther having a protrusion portion above the cover portion 12α.

FIG. 7 is a sectional view of a radar cover 22, which is mounted on avehicle, according to a second embodiment. As illustrated in FIG. 7, theradar cover 22 according to the second embodiment has a cover portion22α, a lower protrusion portion 22β, and an upper protrusion portion22γ. The cover portion 22α is a portion which has a function similar tothat of the cover portion 12α, and the lower protrusion portion 22β is aportion which has a function similar to that of the lower protrusionportion 12β, and detailed description of the cover portion 22α and thelower protrusion portion 22β is omitted.

The upper protrusion portion 22γ is a portion which is provided abovethe cover portion 22α and protrudes on the surface side of the radarcover 22 with respect to the cover portion 22α. The radar cover 22 hasthe upper protrusion portion 22γ, thereby preventing water drops anddirt coming from above from adhering to the cover portion 22α.

A state where water drops and dirt are prevented from adhering to thecover portion 22α is described below with reference to FIG. 8. FIG. 8 isa diagram illustrating a state where water drops coming from below andabove adhere to the radar cover 22 according to the second embodiment.

In FIG. 8, water drops are schematically represented as circles, anddirections from which the water drops are coming are schematicallyrepresented by arrows. For example, when it rains, rain drops fall fromabove the vehicle 100. Here, the rain drops coming from above adhere toan upper surface of the upper protrusion portion 22γ which protrudes ona surface side with respect to the cover portion 22α, whereby the waterdrops do not adhere to the cover portion 22α which is located below andbehind the upper protrusion portion 22γ. That is, the upper protrusionportion 22γ plays a role as a so-called rain visor so as to prevent thewater drops from adhering to the cover portion 22α.

Further, when the vehicle 100 runs in the rain, water drops aresometimes thrown up from below due to a wheel rotation, an aerodynamicforce or the like. As described in the first embodiment, the water dropscoming from below the radar cover 22 are prevented by the lowerprotrusion portion 22β from adhering to the cover portion 22α.

As described above, the radar cover 22 according to the secondembodiment of the present invention is capable of preventing the waterdrop coming from above from adhering to the cover portion 22α as well asthe water drops coming from below. Accordingly, the radar cover 22, aswell as the radar cover 12 according to the first embodiment, preventsthe water drops from adhering to the cover portion 22α through which theelectromagnetic waves that are transmitted from and received by theantenna 111 are transmitted, thereby preventing attenuation of theelectromagnetic waves. Consequently, the processing unit 112 accuratelymeasures a propagation distance and a propagation direction of theelectromagnetic waves so as to accurately detect a location of an objectwhich reflects the electromagnetic waves.

In the above-described first embodiment and second embodiment, anexample is described where the radar cover 12 is attached to the rearbumper 50 so as to cover the antenna 111. However, a mounting place isnot limited to the rear bumper 50 as long as the radar cover 12 ismounted on the vehicle so as to cover the transmission-and-receptionsurface 111S with the cover portion 12α. For example, when a vehicle onwhich the radar cover is to be mounted is a vehicle having a back door,the radar cover may be mounted on an upper portion of the back door as arear roof spoiler.

Further, in the first embodiment and the second embodiment, an exampleis described where when the risk of a crash between the vehicle 100 andthe detected object is high, the processing unit 112 performs controlfor making the hazard lamp 13 blink. Alternatively, the processing unit112 may make another in-vehicle device such as an occupant protectiondevice or the like which is mounted on the vehicle 100 operate. Forexample, when the vehicle 100 is equipped with a headrest having a drivemechanism which is electrically movable in a front-back direction of thevehicle, the processing unit 112 performs control to protect an occupantby operating the drive mechanism of the headrest. Specifically, in theprocessing in the above-described step A5, the processing unit 112 makesthe headrest move forward until the headrest touches the head of theoccupant so as to protect the head of the occupant. Owing to suchcontrol, the occupant is protected from the crash impact and preventedfrom a whiplash injury or the like.

INDUSTRIAL APPLICABILITY

The in-vehicle radar device and the cover for the in-vehicle radardevice according to the present invention are useful as, for example, anin-vehicle radar device, a cover for the in-vehicle radar device whichare capable of accurately detecting an object.

1. An in-vehicle radar device which radiates electromagnetic waves andreceives reflected waves, from an object, of the electromagnetic wavesso as to detect a location of the object and which is mounted on a rearof a vehicle, the in-vehicle radar device comprising: atransmission-and-reception section that transmits the electromagneticwaves and receives the reflected waves; a detection section that detectsthe location of the object based on the reflected waves; and a covermember that is provided below a rear bumper of the vehicle and thatcovers the transmission-and-reception section in a manner that a rearsurface of the cover member faces a transmission-and-reception surfaceof the transmission-and-reception section so as to be spaced aparttherefrom, wherein the cover member includes at least a cover portionthat is formed from a material through which electromagnetic waves aretransmitted and that covers the transmission-and-reception surface, anda lower protrusion portion that is provided below the cover portion andformed so as to protrude beyond a surface side of the cover member withrespect to the cover portion, the lower portion having a convex shapeand the cover portion having a concave shape.
 2. The in-vehicle radardevice according to claim 1, wherein the cover member further includesan upper protrusion portion which is provided above the cover portionand formed to protrude on the surface side of the cover member withrespect to the cover portion.
 3. The in-vehicle radar device accordingto claim 2, wherein the cover portion, the lower protrusion portion, andthe upper protrusion portion are integrally formed.
 4. The in-vehicleradar device according to claim 1, further comprising: a crash riskdetermination section that determines whether or not a risk of a crashbetween the object and the vehicle is high based on the detectedlocation of the object; and an information section that providesinformation to rearward of the vehicle of the risk of a crash when therisk of a crash between the object and the vehicle is determined to behigh.
 5. The in-vehicle radar device according to claim 1, furthercomprising: a crash risk determination section that determines whetheror not a risk of crash between the object and the vehicle is high basedon the detected location of the object; and an occupant protectionsection that protects an occupant in the vehicle from the risk of acrash when the risk of crash between the object and the vehicle isdetermined to be high.
 6. The radar device according to claim 5, whereinthe occupant protection section protects the occupant from a crashimpact when the risk of crash between the object and the vehicle isdetermined to be high, by making a headrest equipped on the vehicle moveforward so as to support the head of the occupant.
 7. The in-vehicleradar device according to claim 1, wherein the cover portion is moldedfrom a synthetic resin through which the electromagnetic waves aretransmitted.